xii Contents 



PAGES 



synthesis The course of photosynthesis The demonstra- 

 tion of photosynthesis The formation of sugar and starch 

 The diffusion process The amount of carbon dioxid 

 Light the source of energy Efficiency of the food-making 

 apparatus Light, intensity and quality Temperature 

 Organic matter, rate of production Laboratory work 

 References 195-225 



CHAPTER X 



THE RELATION TO NITROGEN 



Combined nitrogen The nitrogen content of plants Synthesis 

 of nitrogenous bodies Soil nitrogen Nitrites Nitrates 

 - Compounds of ammonium - - The sources of soil nitrates 

 and ammonia Ammonification Nitrification Nitrifying 

 organisms Conditions favoring nitrification Denitrifica- 

 tion Nitrogen fixation Organisms which fix free nitro- 

 gen Bacteria of leguminous tubercles Certain saprophy tic 

 soil bacteria Fungi Mycorhizal fungi General sources 

 of supply of nitrogen Electric fixation of nitrogen 

 Laboratory work References ... . 226-249 



CHAPTER XI 



PRODUCTS OF METABOLISM ; DIGESTION AND TRANSLOCATION 



Metabolism - - Temporary foods, storage products, and perma- 

 nent structures Annuals, biennials, and perennials Car- 

 bohydrates Sugars Starches Cellulose Fats and oils 



- Proteins Classes of proteins Amides Organic acids 



- Tannins - - Resins and turpentine Digestion Diges- 

 tion in different organisms r Enzymes and enzyme action 

 Carbohydrate enzymes and their products Protein enzymes 

 Conduction of digested foods - - Ringing - - Laboratory 

 work References . 250-279 



